Photodetector designs for low-noise, broadband, and high-power applications

Gray, Malcolm B.; Shaddock, D. A.; Harb, C. C.; Bachor, Hans‐A.

doi:10.1063/1.1149175

Cited by 63 publications

(36 citation statements)

References 5 publications

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“…Above 7.0 mW the loss of linearity can be ascribed to PIN and transimpendance amplifiers saturation, cfr. [29] and [30]. By considering the region between 0.5 mW and 6.5 mW, a linear fit gives the angular coefficient m = 0.0108 V 2 /W and the intercept a = 2.579·10 −5 V 2 .…”

Section: Methodsmentioning

confidence: 99%

Source-Device-Independent Ultrafast Quantum Random Number Generation

Marangon¹,

Vallone²,

Villoresi³

2017

Phys. Rev. Lett.

137

126

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Secure random numbers are a fundamental element of many applications in science, statistics, cryptography and more in general in security protocols. We present a method that enables the generation of high-speed unpredictable random numbers from the quadratures of an electromagnetic field without any assumption on the input state. The method allows to eliminate the numbers that can be predict due the presence of classical and quantum side information. In particular, we introduce a procedure to estimate a bound on the conditional min-entropy based on the Entropic Uncertainty Principle for position and momentum observables of infinite dimensional quantum systems. By the above method, we experimentally demonstrated the generation of secure true random bits at a rate greater than 1 Gbit/s.Introduction -Quantum Random Number Generators (QRNG) exploits intrinsic probabilistic quantum processes to generate true random numbers. Indeed, the expression "QRNG" was first introduced for a device based on the decay of radioactive nuclei [1]. Afterwards, QRNGs exploiting the versatility of light were realized: such devices are based on optical processes such as photon welcher weg [2][3][4], photon time of arrival [5][6][7] or vacuum quadratures [8][9][10][11].Usually, the assessment of the randomness of the generated numbers is obtained by applying statistical tests on the output bits. In most of the QRNGs, passing the tests is the only method used to certify the randomness. In case of failure (attributed to hardware problem since the process is assumed to be "random"), numbers are algorithmically post-processed until the tests are passed.However, this procedure con only certifies that the numbers are identically and independently distributed (i.i.d.) with respect to those [12] applied tests. Indeed, a posteriori statistical tests cannot certify that the numbers are not known to someone possessing side information about the generator. For instance, it is not possible to eliminate hardware noise, which is a source of classical side information for an eavesdropper, Eve, who may be able to control it. Hence, a statistical test a posteriori cannot establish whether the numbers are originated by the quantum process or by the noisy hardware. Moreover, even assuming a QRNG with an ideal noiseless hardware, a statistical test cannot reveal whether the outputs arise from a a quantum measurements and then are intrinsically random. For instance, a polarization welcher weg QRNG with an optical source emitting photons in a completely mixed polarization state can be seen as the photonic version of a fair coin. The random sequence can be predicted by Eve if she knows "the coin's equations of motion" (namely she has classical side information) or if she holds a quantum system correlated with the QRNG (namely she has quantum side information).The quantity that evaluates the amount of side information on a random sequence Z is the so called conditional quantum min-entropy H min (Z|E) [13]. However, such min-entropy is generally hard to estimate....

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Section: Methodsmentioning

confidence: 99%

Source-Device-Independent Ultrafast Quantum Random Number Generation

Marangon¹,

Vallone²,

Villoresi³

2017

Phys. Rev. Lett.

137

126

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“…large signal-to-noise ratio (SNR) of 10 dB or more at the analysis frequency of 2.0 MHz for a certain input laser power [1][2][3][4]. Conventionally, the SNR could be enlarged by boosting the current-to-voltage gain, increasing the input laser power, or equivalently by reducing the electronic noise at the analysis frequency of 2.0 MHz [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

A Low-Noise, Large-Dynamic-Range-Enhanced Amplifier Based on JFET Buffering Input and JFET Bootstrap Structure

et al. 2015

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We report a low-noise, and high-dynamic-range amplifier based on transimpedance amplifier (TIA) for detecting shot noise of 1064 nm laser in quantum optical experiments. Compared with a single junction field effect transistor (JFET) buffered TIA, the electronic noise is effectively 2.8 dB suppressed at the analysis of 2.0 MHz, and 4.0 dB suppressed at 4.0 MHz by means of a JFET bootstrap structure. Under the transimpedance gain of 200 kΩ & 0.5 pF, the measured shot noise at the injected laser power of 51 μW is 12.5 dB above the electronic noise at 2.0 MHz, and 9.8 dB at 4.0 MHz. With adjusting of bias condition of the ETX500 and application of a L-C (inductance and capacitance) structure, the dynamic range is largely boosted from the original 1.52 mW to 11.22 mW. The amplifier meets the requirement of SNR for Bell-state detection in quantum optical experiments. Index Terms-TIA, low noise, large dynamic range, JFET buffering, JFET bootstrap, L-C structure, Bell-state detection, quantum optical experiments.

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“…The difference in photocurrents is amplified and multiplied by a sinusoidal current of frequency Ω produced by a signal generator, and filtered by a 100 kHz low-pass filter in order to obtain the instantaneous value of the photocurrent Fourier component at frequency Ω, which is then recorded by an A/D board installed in a PC, which also simultaneously records the instantaneous value of the DC photocurrent. In direct detection with a photodetector, assuming that most electrons in the current are photoelectrons, the number of photoelectons measured by the detector is proportional to the photon number of the input state [17]. Since the output from the detector is difference in current, the recorded data are proportional to the difference in photoelectron number, which carries information about the photon number difference of the two beams.…”

Section: Quantum Communication Channel With Twin Beamsmentioning

confidence: 99%